Takeuchi, I.organized Dictyostelium cDNA project with several members of this research group and started in the last autumn. He also found that prestalk and prespore cells sucked into a capillary tube do not differentiate at a constant propotion, as in ordinary slugs.Molecular mechanism of morphogenesis Suto, K.analyzed a REMI mutant which dose not develop after aggregation, and found that the mutated genes is a homologue of SSN6 gene of yeast. Ochiai, H.prepared rabbit polyclonal antibody raised against the membrance fraction isolated from Polysphondylium cells transformed with an antisence RNA-expressing plasmid to reduce cell-adhesion protein. As the antibody efficiently inhibits Polysphondylium cell-adhesion, it will be a good tool to analyze the mechanism in the formation of multeicellular structure of the organism. Molecular machanism of differentiation To investigate a switch mechanism from growth to differentiation, Maeda, Y.cloned two genes (Quit2,3) which are expressed around
… More the critical point (PS point) of the cell cycle. He found that Quit2 encodes a new calcium-binding protein and Quit3 has a sequence coding for the complementary strand of annexin Vll gene. Oohata, A.isolated a factor induction of prespore differentiation in vitro. Maeda, M.revealed that the gene is essential for aggregation and that hetero-trimeric G proteins are not required for this regulation. Tanaka, Y.established the techniques for an insertional mutagenesis with Polysphondylium cells by the use of REMI method. Ishida, S.isolated 'sporogenous mutant', in which even single cells differentiate into spores and tag mutants which stop at the 'tight aggregate' stage. Urushihara, H.analyzed two sorts of REMI mutants (TMC1 and MCF1). TMC1 was normal for sexual cell fusion, but was unusual for chemotaxis. MCF1 had a defect in sexual cell fusion.細胞分化の分子機構 前田(靖)は増殖・分化の切り替えの分子機構を知るために、細胞周期上の増殖分化の分岐点(PS点)前後で特異的に発現する遺伝子(Quit2,Quit3)について調べ、Quit2は新規のカルシュウム結合性タンパク質をコードしており、Quit3はアネキシンVII遺伝子の相補鎖をコードしていることを明らかにした。大畠は予定胞子細胞の分化誘導因子を単一標品に精製した。前田(ミ)は挿入突然変異法により得たMAPカイネースの欠損株を解析して、この遺伝子は集合に必須であること、またその活性調節には3量体Gタンパク質は関与していないことを明らかにした。田仲はPolysphondyliumの挿入突然変異体の作製方法を確立した。この方法を用いて得られた形質転換体を解析して、ベクターDNAがゲノムDNAにランダムに1コピーで挿入されているので有用な方法であると結論した。石田は単細胞で胞子に分化するsporogenous変異体と"固い集合体"で発生の停止するtag変異体を挿入突然変異体法で分離し、それらの遺伝子を同定した。小山は浸透圧ストレス耐性の変異株を挿入突然変異体により作製する条件を検討している。 Less